Build Truth with `-source 8 -target 8`, updating annotations appropriately.

This is a small step in the general direction of https://github.com/google/truth/issues/746

While there, improve the documentation of deprecated `LiteProtoSubject.isEqualTo(MessageLite.Builder)` and `isNotEqualTo(MessageLite.Builder)`, and add a TODO about possible future steps.

RELNOTES=Truth is now built with `-source 8 -target 8`. This means that it no longer runs under Java 7 VMs. It continues to run under Android, even old versions, for all apps that have [enabled support for Java 8 language features](https://developer.android.com/studio/write/java8-support#supported_features).
PiperOrigin-RevId: 388266403
29 files changed
tree: e203ccad09b2acac778d0b5f8e24b7dcb1391193
  1. .github/
  2. core/
  3. extensions/
  4. refactorings/
  5. util/
  6. .gitignore
  7. CONTRIBUTING.md
  8. LICENSE
  9. overview.html
  10. pom.xml
  11. README.md
README.md

Main Site Build Status Maven Release Stackoverflow

What is Truth?

Truth makes your test assertions and failure messages more readable. Similar to AssertJ, it natively supports many JDK and Guava types, and it is extensible to others.

Truth is owned and maintained by the Guava team. It is used in the majority of the tests in Google’s own codebase.

Read more at the main website.